Hi there...

I'm currently riding with a 18t cog and 48 sprocket. What would be the advantage of reducing the cog size. I noticed alot of people ride 16t.

Better bar-spins of course. Duh?!?!?

lower number of teeth=higher gear ratio.

go faster

would you keep the same sprocket if you went down in size on the cog?

What you're referring to is usually called the chainring. Technically both the rear cog and chainring are sprockets.

Yes you can keep the same chainring if you buy a new cog with less teeth.

There are two common standards today when it comes to sprockets and the chain though. The more road standard, 3/32, and the more track standard, 1/8. This just refers to the width of the chain in inches, be sure your drive chain works together before you buy anything.

16 harder to start less low speed control higher top speed
18 better low speed control better acceleration less top speed

thanks bud...extremely helpful. cheers!

a lot of people ride on 48x16 because that comes stock on a lot of off the peg track bikes.

1/8 chains will work on 3/32 cogs/chainrings, but you might as well make sure they all match up.

Yea that's what I'm doing right now, kind of sucks.

don't do 48/16 if you're going brakeless. only 1 skidpatch

i just changed my cog from a 16 to a 17 (more for skidding then anything else) but i'm amazed at the difference one t made. Easier start and acceleration for sure. If you want to skid, go for any prime number cog or chainring.

While were on the subject; does a larger or smaller chainring do anything different, or is it the same effect as changing the cog?

opposite effect

Larger chainring = higher gear ratio
Smaller cog = higher gear ratio

clear and to the point. thank you!